This application claims the benefit of Korean Patent Applications No. 2000-20722 filed on Apr. 19, 2000 and No. 2000-45988 filed on Aug. 8, 2000, which are hereby incorporated by reference as if fully set forth herein.
1. Field of the Invention
The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device implementing in-plane switching (IPS) where an electric field to be applied to liquid crystal is generated in a plane parallel to a substrate.
2. Discussion of the Related Art
A typical liquid crystal display (LCD) device uses optical anisotropy and polarization properties of liquid crystal molecules. The liquid crystal molecules have a definite orientational order in alignment resulting from their thin and long shapes. The alignment orientation of the liquid crystal molecules can be controlled by supplying an electric field to the liquid crystal molecules. In other words, as the alignment direction of the electric field is changed, the alignment of the liquid crystal molecules also changes. Because incident light is refracted to the orientation of the liquid crystal molecules due to the optical anisotropy of the aligned liquid crystal molecules, image data is displayed.
A liquid crystal is classified into a positive liquid crystal and a negative liquid crystal, in view of electrical property. The positive liquid crystal has a positive dielectric anisotropy such that long axes of liquid crystal molecules are aligned parallel to an electric field. Whereas, the negative liquid crystal has a negative dielectric anisotropy such that long axes of liquid crystal molecules are aligned perpendicular to an electric field.
By now, an active matrix LCD that the thin film transistors and the pixel electrodes are arranged in the form of a matrix is most attention-getting due to its high resolution and superiority in displaying moving video data.
FIG. 1 is a cross-sectional view illustrating a typical twisted nematic (TN) LCD panel. As shown in FIG. 1, the TN-LCD panel has lower and upper substrates 2 and 4 and an interposed liquid crystal layer 10. The lower substrate 2 includes a first transparent substrate 1a and a thin film transistor (xe2x80x9cTFTxe2x80x9d) xe2x80x9cSxe2x80x9d. The TFT xe2x80x9cSxe2x80x9d is used as a switching element to change orientation of the liquid crystal molecules. The lower substrate 2 further includes a pixel electrode 15 that applies an electric field to the liquid crystal layer 10 in accordance with signals applied by the TFT xe2x80x9cSxe2x80x9d. The upper substrate 4 has a second transparent substrate 1b, a color filter 8 on the second transparent substrate 4, and a common electrode 14 on the color filter 8. The color filter 8 implements color for the LCD panel. The common electrode 14 serves as another electrode for applying a voltage to the liquid crystal layer 10. The pixel electrode 15 is arranged over a pixel portion xe2x80x9cP,xe2x80x9d i.e., a display area. Further, to prevent leakage of the liquid crystal layer 10 between the lower and upper substrates 2 and 4, those substrates are sealed by a sealant 6.
As described above, because the pixel and common electrodes 15 and 14 of the conventional TN-LCD panel are positioned on the lower and upper substrates 2 and 4, respectively, the electric field induced therebetween is perpendicular to the lower and upper substrates 1a and 1b. The above-mentioned liquid crystal display device has advantages of high transmittance and aperture ratio, and further, since the common electrode on the upper substrate serves as an electrical ground, the liquid crystal is protected from a static electricity.
FIGS. 2A and 2B show different alignments of the positive TN liquid crystal molecules 10, respectively, without and with an electric field (off and on states). In FIG. 2A, various arrows show the gradual rotating of the liquid crystal molecules 10 with polar angles 0 to 90 degrees, which are measured on a plane parallel to the lower and upper substrate 2 and 4. At the same time, the liquid crystal molecules 10 are gradually rotated to 90 degrees from the lower substrate 2 to the upper substrate 4. That is to say, the long axes of the liquid crystal molecules 10 gradually rotate along a helical axis (not shown) that is perpendicular to the lower and upper substrates 2 and 4. First and second polarizers 18 and 30 are positioned, respectively, on the exterior surfaces of the lower and upper substrates. Referring to FIG. 2A, the broken lines on the first and second polarizers 18 and 30 correspond to first and second transmittance axis of the first and second polarizers 18 and 30, respectively. After rays of light travel through a TN liquid crystal panel in the off state, as described above, they are linearly polarized and rotated 90 degrees.
As shown in FIG. 2B, when there is an electric field xe2x80x9cExe2x80x9d applied to the positive TN liquid crystal molecules 10, the liquid crystal molecules are aligned perpendicular to the upper and lower substrates 4 and 2. That is to say, with the electric field xe2x80x9cExe2x80x9d applied across the liquid crystal molecules 10, the liquid crystal molecules 10 rotate to be parallel to the electric field xe2x80x9cExe2x80x9d. In this case, the rotation of the linearly polarized light does not take place. Therefore, light is blocked by the second polarizers 30 after it travels through the first polarizer 18.
However, the above-mentioned operation mode of the TN-LCD panel has a disadvantage of a narrow viewing angle. That is to say, the TN liquid crystal molecules rotate with polar angles 0 to 90 degrees, which are too wide. Because of the large rotating angle, contrast ratio and brightness of the TN-LCD panel fluctuate rapidly with respect to the viewing angles.
To overcome the above-mentioned problem, an in-plane switching (IPS) LCD panel was developed. The IPS-LCD panel implements a parallel electric field that is parallel to the substrates, which is different from the TN or STN (super twisted nematic) LCD panel. A detailed explanation about operation modes of a typical IPS-LCD panel will be provided with reference to FIGS. 3, 4A, and 4B.
As shown in FIG. 3, first and second substrates 1a and 1b are spaced apart from each other, and a liquid crystal xe2x80x9cLCxe2x80x9d is interposed therebetween. The first and second substrates 1a and 1b are called an array substrate and a color filter substrate, respectively. Pixel and common electrodes 15 and 14 are disposed on the first substrate 1a. The pixel and common electrodes 15 and 14 are parallel with and spaced apart from each other. On a surface of the second substrate 1b, a color filter 25 is disposed opposing the first substrate 1a. The pixel and common electrodes 15 and 14 apply an electric field xe2x80x9cExe2x80x9d to the liquid crystal xe2x80x9cLCxe2x80x9d. The liquid crystal xe2x80x9cLCxe2x80x9d has a negative dielectric anisotropy, and thus it is aligned parallel to the electric field xe2x80x9cExe2x80x9d.
FIGS. 4A and 4B conceptually illustrate operation modes for a typical IPS-LCD device. In an off state, the long axes of the LC molecules xe2x80x9cLCxe2x80x9d maintain a definite angle with respect to a line that is perpendicular to the pixel and common electrodes 15 and 14. The pixel and common electrode 15 and 14 are parallel with each other. Herein, the angle difference is 45 degrees, for example.
In an on state, an in-plane electric field xe2x80x9cExe2x80x9d, which is parallel with the surface of the first substrate 1a, is generated between the pixel and common electrodes 15 and 14. The reason is that the pixel electrode 15 and common electrode 14 are formed together on the first substrate 1a. Then, the LC molecules xe2x80x9cLCxe2x80x9d are twisted such that the long axes thereof coincide with the electric field direction. Thereby, the LC molecules xe2x80x9cLCxe2x80x9d are aligned such that the long axes thereof are perpendicular to the pixel and common electrodes 15 and 14.
In the above-mentioned IPS-LCD panel, there is no transparent electrode on the color filter, and the liquid crystal used in the IPS-LCD panel includes a negative dielectric anisotropy.
FIGS. 5A and 5B are conceptual plane views illustrating alignment of the liquid crystal molecules of the above-mentioned IPS-LCD panel, respectively, in off and on states. As shown in FIG. 5A, each liquid crystal molecule 10 is aligned in a proper direction by a pair of alignment layers (not shown), which are formed on opposing surfaces of the first and second substrate 1a and 1b. As shown in FIG. 5B, the electric field xe2x80x9cExe2x80x9d is applied between the pixel and common electrodes 15 and 14 such that each molecule 10 is aligned in accordance with the electric field xe2x80x9cExe2x80x9d. That is to say, each liquid crystal molecule 10 rotates to a definite angle in accordance with the electric field xe2x80x9cExe2x80x9d.
Compared with the TN-LCD device of FIG. 1, the IPS-LCD device has a wider viewing angle owing to a smaller rotating angle of the liquid crystal molecules.
The IPS-LCD device has the advantage of a wide viewing angle. Namely, when a user looks at the IPS-LCD device in a top view, the wide viewing angle of about 70 degrees is achieved in up, down, right and left directions.
By the above-mentioned operation modes and with additional elements such as polarizers and alignment layers, the IPS-LCD device displays images. The IPS-LCD device has a wide viewing angle, low color dispersion qualities, and the fabricating processes thereof are simpler among those of various LCD devices.
However, because the pixel and common electrodes are disposed on the same plane on the lower substrate, the transmittance and aperture ratio are low. In addition, a response time according to a driving voltage should be improved, and a color""s dependence on the viewing angle should be decreased.
FIG. 6 is a graph of the CIE (Commission Internationale de l""Eclairage) color coordinates and shows the color dispersion property of the conventional IPS-LCD device. The horseshoe-shaped area is the distribution range of the wavelength of visible light. The results are measured using point (0.313, 0.329) in CIE coordinate as a standard white light source and with various viewing angles of right, left, up and down, and 45 and 135 degrees. Obviously, the range of the color dispersion is so long, which means that the white light emitted from the conventional IPS-LCD device is dispersed largely according to the viewing angle. This results from the fact that the operation mode of the IPS-LCD device is controlled by birefringence. S. Endow et al. indicated the above-mentioned problem in their paper xe2x80x9cAdvanced 18.1-inch Diagonal Super-TFT-LCDs with Mega Wide Viewing Angle and Fast Response Speed of 20 ms: IDW 99"" 187 pagexe2x80x9d.
FIG. 7 is a graph illustrating transmittance with respect to viewing angles for first to eighth gray levels (gray scale) of a conventional IPS-LCD device. Except for the first gray level, xe2x80x9clevel 1,xe2x80x9d each gray level has the highest transmittance at a viewing angle of 0 degree. The first gray level, xe2x80x9clevel 1 xe2x80x9d has gray inversion regions. When the viewing angle is beyond 60 degrees, the first gray level, xe2x80x9clevel 1,xe2x80x9d has the higher transmittance than the fourth gray level, xe2x80x9clevel 4 xe2x80x9d. The first gray level, xe2x80x9clevel 1,xe2x80x9d should implement a black state of the LCD panel. However, gray inversion occurs at viewing angles larger than 60 degrees, such that a white state, but not a black state, is produced at the larger viewing angles. The above-mentioned gray inversion results from a birefringence dependence of the IPS-LCD device and causes poor display quality of the IPS-LCD device.
To achieve the wide viewing angle and an improved color dispersion property, the common and pixel electrodes for the IPS-LCD device are designed to have various shapes. FIG. 8 illustrates a first example of the IPS-LCD device according to a related art. As shown in FIG. 8, a plurality of pixel and common electrode 15 and 14 are alternately arranged on a substrate (reference 1a of FIG. 3) having a thin film transistor xe2x80x9cSxe2x80x9d. At this point, an alignment layer (not shown) is formed on the substrate (not shown). The alignment layer has first and second rubbing directions 40a and 40b, respectively, in accordance with first and second domains xe2x80x9cAxe2x80x9d and xe2x80x9cBxe2x80x9d such that a multi-domain for liquid crystal molecules 10 is achieved.
Therefore, the liquid crystal molecules 10 are divided into first and second liquid crystal portions 10a and 10b, which correspond to the first and second domains xe2x80x9cAxe2x80x9d and xe2x80x9cBxe2x80x9d, respectively. In accordance with the first and second rubbing directions 40a and 40b, the first and second liquid crystal portions 10a and 10b are aligned to have symmetric pretilt angles. The above-mentioned multi-domain has advantages of preventing color filter shift and achieving the wide viewing angle.
FIGS. 9A and 9B, respectively, show expanded views of the first and second domains xe2x80x9cAxe2x80x9d and xe2x80x9cBxe2x80x9d of FIG. 8. In the off state, the first and second liquid crystal portions 10a and 10b (broken lines) are aligned in accordance with the first and second rubbing directions 40a and 40b, respectively.
Therefore, the first and second liquid crystal portions 10a and 10b are respectively aligned to have symmetric pretilt angles. Whereas, when an electric field xe2x80x9cExe2x80x9d is applied between the pixel and common electrodes 15 and 14, the first and second liquid crystal portions 10a and 10b (continuous lines) are aligned in accordance with the electric field xe2x80x9cExe2x80x9d. Therefore, the first and second liquid crystal portions 10a and 10b are aligned in the same direction. In other words, a single-domain is present for the on state, or the white state.
The above-mentioned single-domain of the on state causes a narrow viewing angle and a color shift. For example, instead of white, yellow is displayed when a user watches along short axes of the liquid crystal molecules, and blue is displayed when the user watches along long axes of the liquid crystal molecules.
FIG. 10 shows a second example of the IPS-LCD device according to the related art. As shown, zigzag-shaped pixel electrodes 35 and zigzag-shaped common electrodes 34 are alternately arranged such that first and second electric fields 46a and 46b are alternately induced along the zigzag-shaped electrodes. The first and second electric fields 46a and 46b have different directions. Therefore, a multi-domain is achieved owing to the first and second electric fields 46a and 46b. An alignment layer (not shown) is also used for a first state alignment of liquid crystal molecules (reference 10 of FIG. 8). The alignment layer (not shown) beneficially has one rubbing direction 60 instead of the first and second rubbing directions 40a and 40b of FIG. 8. In comparison with the first example shown in FIG. 8, many more domains are produced by the second example.
The above-mentioned zigzag-shaped common and pixel electrodes 34 and 35 minimize the color shift. However, between bending portions xe2x80x9cDxe2x80x9d of the common and pixel electrodes 34 and 35, an electric field is induced perpendicular to the rubbing direction 44. That is to say, long axes of the liquid crystal molecules are perpendicular to the electric field induced between the bending portions xe2x80x9cDxe2x80x9d. Then, the liquid crystal molecules cannot rotate but keep the first state alignment such that an abnormal alignment is present at each boundary portion xe2x80x9cCxe2x80x9d between the different domains.
The abnormal alignment at the boundary portion xe2x80x9cCxe2x80x9d causes a light leak such that white lines are shown on a display area, the pixel region xe2x80x9cPxe2x80x9d shown in FIG. 1, of the LCD device. The above-mentioned white lines are called a disclination. A black matrix may be expanded to the pixel regions to cover the disclination. However, the expanded black matrix causes a low aperture ratio.
Now, with reference to FIGS. 11A and 11B, effect of the multi-domain is explained in detail. A liquid crystal layer generally has a birefringence, because each liquid crystal molecule has a long and thin shape. The birefringence changes with respect to a viewing angle. FIG. 11A is a cross-sectional view illustrating a single-domain for a liquid crystal molecule 10 between upper and lower polarizers 30 and 18. At this point, the birefringence of the liquid crystal molecule 10 involves different values for the first, second, and third position xe2x80x9caxe2x80x9d, xe2x80x9cbxe2x80x9d, and xe2x80x9ccxe2x80x9d, which involve different viewing angles. Therefore, the birefringence of the liquid crystal molecule 10 cannot be zero with respect to viewing angles. If the birefringence of the liquid crystal layer is not zero, the perfect black state cannot be achieved between the upper and lower polarizers 30 and 18.
To overcome the above-mentioned problem, the multi-domain shown in FIG. 11B is adopted for a LCD device. As shown, there are first and second liquid crystal molecules 10a and 10b arranged opposite to each other. The birefringence of the first liquid crystal molecule 10a involves different values for the first, second, and third position xe2x80x9ca1xe2x80x9d,xe2x80x9cb1xe2x80x9d,and xe2x80x9cc1xe2x80x9d. Whereas, the birefringence of the second liquid crystal molecule 10b involves different values for the fourth, fifth, and sixth position xe2x80x9ca2xe2x80x9d,xe2x80x9cb2xe2x80x9d, and xe2x80x9cc2xe2x80x9d. The first and fourth positions xe2x80x9ca1xe2x80x9d and xe2x80x9ca2xe2x80x9d involve the same viewing angle. Because the first and second liquid crystal molecules 10a and 10b are symmetrically opposed with each other, a birefringence of the first liquid crystal molecule 10a at the first position xe2x80x9ca1xe2x80x9d is compensated by that of the second liquid crystal molecule 10b at the fourth position xe2x80x9cb2xe2x80x9d. That is to say, each birefringence of the first liquid crystal molecule 10a is compensated by corresponding birefringence of the second liquid crystal molecule 10b. In other words, sum of the birefringence between the first and second liquid crystal molecules 10a and 10b is about zero. Accordingly, the multi-domain shown in FIG. 11B improves the display quality of the LCD device.
Accordingly, the present invention is directed to an IPS-LCD device that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.
An object of the present invention is to provide an IPS-LCD device having low color dispersion and low white inversion with respect to viewing angles.
Another object of the present invention is to provide an IPS-LCD device having optimized common and pixel electrodes such that high aperture ratio, low color shift, and fast response time are achieved.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
In order to achieve the above object, the first preferred embodiment of the present invention provides an array substrate for an IPS-LCD device. The array substrate includes: a substrate; a gate line on the substrate; a data line perpendicular to the gate line; a thin film transistor at a crossing portion between the gate and data lines; a common line parallel to the gate line; a plurality of common electrodes perpendicular to the common line, wherein the common electrodes are spaced apart from each other and at least one of the common electrodes is divided into first and second portions that are co-linear and separated by a predetermined distance; and a plurality of pixel electrodes parallel to the plurality of common electrodes, wherein the plurality of pixel and common electrodes are alternately arranged such that the array substrate is used for the IPS-LCD device.
The first and second portions of the common electrode are about equal in length such that first and second domains for a liquid crystal are produced by the array substrate. Beneficially, the pixel electrode adjacent the first and second portions of the common electrode includes a male electrode opposing a boundary between the first and second portions of the common electrode.
At least one of the pixel electrodes is divided into first and second portions that are co-linear and spaced apart by a predetermined distance. The second portions of the common and pixel electrodes are about twice as long as the first portions of, respectively, the common and pixel electrodes, the first portion of the common electrode opposes the second portion of the pixel electrode, and the second portion of the common electrode opposes the first portion of the pixel electrode. Beneficially, the common electrode adjacent the pixel electrode includes a male electrode that opposes a boundary between the first and second portions of the pixel electrode. In addition, the pixel electrode adjacent the common electrode beneficially includes a male electrode that opposes a boundary between the first and second portions of the common electrode.
The pixel electrode is selected from a group consisting of indium tin oxide (ITO) and indium zinc oxide (IZO). The common electrode is selected from a group consisting of chromium (Cr), aluminum (Al), aluminum alloy (Al alloy), molybdenum (Mo), tantalum (Ta), tungsten (W), antimony (Sb), and an alloy thereof, or is beneficially selected from a group consisting of indium tin oxide (ITO) and indium zinc oxide (IZO).
In another aspect, the present invention provides an array substrate for an IPS-LCD device. The array substrate includes: a substrate; a gate line on the substrate; a data line perpendicular to the gate line; a thin film transistor at a crossing portion between the gate and data lines; a main common line parallel to the gate line; first and second auxiliary common lines perpendicular to the main common line, the first and second auxiliary common lines being parallel to and spaced apart from each other; a plurality of common electrodes perpendicular to the first and second auxiliary common lines, wherein the common electrodes being spaced apart from each other and at least one of the common electrodes is divided into first and second portions that are co-linear and separated by a predetermined distance; and a plurality of pixel electrodes parallel to the plurality of common electrodes, wherein the plurality of pixel and common electrodes are alternately arranged such that the array substrate is used for the IPS-LCD device.
The first and second portions are about equal in length such that first and second domains for a liquid crystal are produced by the array substrate. Beneficially, the pixel electrode adjacent the first and second portions of the common electrode includes a male electrode that opposes an boundary between the first and second portions.
At least one of the pixel electrodes is divided into first and second portions that are co-linear and separated by a predetermined distance. The second portions of the common and pixel electrodes are about twice as long as the first portions of, respectively, the common and pixel electrodes, the first portion of the common electrode opposes the second portion of the pixel electrode, and the second portion of the common electrode opposes the first portion of the pixel electrode.
The common electrode adjacent the pixel electrode includes a male electrode that opposes a boundary between the first and second portions of the pixel electrode. The pixel electrode adjacent the common electrode includes a male electrode that opposes a boundary between the first and second portions of the common electrode.
In another aspect, the present invention provides an array substrate for an IPS-LCD device. The array substrate includes: a substrate; a gate line on the substrate; a data line perpendicular to the gate line; a thin film transistor at a crossing portion between the gate and data lines; a common line parallel to the gate line; a plurality of common electrodes extending perpendicular to the common line; a plurality of pixel electrodes arranged alternately with the plurality of common electrodes; an auxiliary common electrode perpendicularly contacting each of the common electrodes; and an auxiliary pixel electrode perpendicularly contacting each of the pixel electrodes, wherein the auxiliary pixel electrodes is spaced apart from the auxiliary common electrode and wherein the plurality of common electrodes and the plurality of pixel electrodes are on a same layer.
In another aspect, the present invention provides an array substrate for an IPS-LCD device. The array substrate includes: a substrate; a gate line on the substrate; a data line perpendicular to the gate line; a thin film transistor at a crossing portion between the gate and data lines; a common line parallel to the gate line, the common line including first and second auxiliary common lines perpendicular to the common line; a plurality of common electrodes extending perpendicular to the first and second auxiliary common lines; a plurality of pixel electrodes arranged alternately with the plurality of common electrodes; an auxiliary common electrode perpendicularly contacting each of the common electrodes; and an auxiliary pixel electrode perpendicularly contacting each of the pixel electrodes, wherein the auxiliary pixel electrodes is spaced apart from the auxiliary common electrode.
In another aspect, the present invention provides an array substrate for an IPS-LCD device. The array substrate includes; a substrate; a gate line on the substrate; a data line perpendicular to the gate line; a thin film transistor at a crossing portion between the gate and data lines; a common line parallel to the gate line, the common line including a plurality of common electrodes extending perpendicular to the common line; a plurality of pixel electrodes arranged alternately with the plurality of common electrodes; a plurality of auxiliary electrodes connecting the plurality of common and pixel electrodes in a check pattern.
In another aspect, the present invention provides an array substrate for an IPS-LCD device. The array substrate includes; a substrate; a gate line on the substrate; a data line perpendicular to the gate line; a thin film transistor at a crossing portion between the gate and data lines; a pixel region surrounded by the gate and data lines, the pixel region including first and second domains; a transparent pixel electrode including (a) first and second perpendicular pixel electrodes, (b) a plurality of first transverse pixel electrodes, and (c) a second transverse pixel electrode, wherein the first perpendicular pixel electrode is disposed along the first and second domains and perpendicular to the gate line, the second perpendicular pixel electrode is disposed on the second domain and parallel to the first perpendicular pixel electrode, the plurality of first transverse pixel electrodes perpendicularly extends from the first perpendicular pixel electrode on the first domain, and the second transverse pixel electrode connects the first and second perpendicular pixel electrodes on the second domain; a common line parallel to the gate line; and a common electrode including (a) first to third perpendicular common electrodes, (b) a plurality of first transverse common electrodes, and (c) a second transverse common electrode, wherein the first and second perpendicular common electrode is disposed along the first and second domains and parallel to the first and second perpendicular pixel electrodes, the third perpendicular common electrode is disposed on the second domain and between the first and second perpendicular common electrodes, the plurality of first transverse common electrodes are alternately arranged with the plurality of transverse pixel electrodes on the first domain, and the second transverse common electrode connects the first to third perpendicular common electrodes.
An outermost first transverse pixel electrode overlaps a portion of the gate line. The common electrode is a transparent conductive material.
The array substrate further includes an alignment layer having first and second rubbing directions, which correspond to the first and second domains, respectively.
In another aspect, the present invention provides a method for fabricating an array substrate of an IPS-LCD device. The method includes: preparing a substrate; forming a gate line including a gate electrode on the substrate; forming a gate-insulating layer on the substrate such that the gate-insulating layer covers the gate line and gate electrode; forming an active layer and ohmic contact layer on the gate-insulating layer; forming a data line including a source electrode, and a drain electrode on the gate-insulating layer; forming a first passivation layer on the gate-insulating layer such that the first passivation layer covers the data line, source electrode, and drain electrode, the gate-insulating layer having a drain contact hole over the drain electrode; forming a pixel electrode on the first passivation layer, the pixel electrode including (a) first and second perpendicular pixel electrodes, (b) a plurality of first transverse pixel electrodes, and (c) a second transverse pixel electrode, wherein the first perpendicular pixel electrode is disposed along the first and second domains and perpendicular to the gate line, the second perpendicular pixel electrode is disposed on the second domain and parallel to the first perpendicular pixel electrode, the plurality of first transverse pixel electrodes perpendicularly extends from the first perpendicular pixel electrode on the first domain, and the second transverse pixel electrode connects the first and second perpendicular pixel electrodes on the second domain; forming a second passivation layer on the pixel electrode; forming a common lines including a common electrode on the second passivation layer, the common electrode including (a) first to third perpendicular common electrodes, (b) a plurality of first transverse common electrodes, (c) and a second transverse common electrode, wherein the first and second perpendicular common electrode is disposed along the first and second domains and parallel to the first and second perpendicular pixel electrodes, the third perpendicular common electrode is disposed on the second domain and between the first and second perpendicular common electrodes, the plurality of first transverse common electrodes are alternately arranged with the plurality of transverse pixel electrodes on the first domain, and the second transverse common electrode connects the first to third perpendicular common electrodes; and forming an alignment layer on the common electrode, the alignment layer having first and second rubbing directions.
The method further includes the step of forming a planar layer on the common electrode before forming the alignment layer.
An outermost first transverse pixel electrode overlaps a portion of the gate line. The common electrode is a transparent conductive material.
The first and second rubbing directions are symmetrical with respect to a line parallel to the gate line.
In another aspect, the present invention provides an array substrate for an LCD-device. The array substrate includes: a substrate; a gate line on the substrate; a data line perpendicular to the gate line; a thin film transistor at a crossing portion between the gate and data lines; a pixel region surrounded by the gate and data lines, the pixel region including first and second domains; transverse pixel and common electrodes disposed on the first domain and parallel to the gate line, the transverse pixel and common electrodes being alternately arranged; perpendicular pixel and common electrodes disposed on the second domain and perpendicular to the transverse pixel and common electrodes, respectively, the perpendicular pixel and common electrodes being alternately arranged; and an alignment layer having first and second rubbing directions, the first and second rubbing directions corresponding to the first and second domains, respectively.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.